Vertical rays are hotter than slanting rays due to the following reasons:
1. Vertical rays heat up a smaller surface. Hence, the heat received per unit of area is large. On the other hand, slanting rays heat up a large area.
2. Vertical rays travel through a shorter distance in the atmosphere and the loss of heat is less. Slanting rays travel a longer distance through the atmosphere where much of its heat is absorbed by clouds, water vapour and dust particles.
